/*
 * Created on 08-Oct-2004
 * Created by Paul Gardner
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

package org.gudy.azureus2.core3.disk;

/**
 * Represents a DiskManager Piece
 * 
 * @author parg
 * @author MjrTom 2005/Oct/08: priority handling 2006/Jan/2: refactoring, mostly to base Piece interface
 */

public interface DiskManagerPiece {
    public DiskManager getManager();

    public int getLength();

    public int getPieceNumber();

    public int getNbBlocks();

    public int getBlockSize(int block_index);

    public short getReadCount();

    public void setReadCount(short c);

    public boolean calcNeeded();

    public void clearNeeded();

    /**
     * @return true if any file the piece covers is neither Do Not Download nor Delete. This is not a real-time indicator. Also, the results are not
     *         reliable for pieces that are Done. Use calcNeeded() for guaranteed correct and up to date results
     * @see calcNeeded(), clearNeeded(), setNeeded(), setNeeded(boolean)
     */
    public boolean isNeeded();

    public void setNeeded();

    public void setNeeded(boolean b);

    // a piece is Written if data has been written to storage for every block (without concern for if it's checked)
    public boolean isWritten();

    public int getNbWritten();

    public boolean[] getWritten();

    /**
     * @param blockNumber
     *            int
     * @return true if the given blockNumber has already been written to disk
     */
    public boolean isWritten(int blockNumber);

    public void setWritten(int blockNumber);

    // a piece is Checking if a hash check has been setup and the hash check hasn't finalized the result yet
    // this flag is asynch, so be careful, and it's also transitory (comapared to most of the others being kinda sticky)

    public void setChecking();

    public boolean isChecking();

    public boolean isNeedsCheck();

    public boolean calcDone();

    /**
     * @return true when the hash check has passed and the DiskManager has asyncronously updated the Done status. There is nothing further to be done
     *         regarding downloading for pieces that are Done.
     */
    public boolean isDone();

    public void setDone(boolean b);

    /**
     * @return true if a piece is Needed and not Done
     */
    public boolean isInteresting();

    /**
     * This must not be used to qualify pieces in End Game Mode.
     * 
     * @return true if a piece is Needed but is not fully; Requested, Downloaded, Written, Checking, or Done.
     */
    public boolean isDownloadable();

    public void setDownloadable();

    /**
     * returns true if all the files that the piece spans are skipped
     * 
     * @return
     */
    public boolean isSkipped();

    public void reDownloadBlock(int blockNumber);

    public void reset();

    public String getString();
}
